Dave's 80:1 RC mid drive kit build log

[Ham]

Which freewheels are people using these days on 3220 kits? I have a gen 1 with a White Ind freewheel that has now developed some serious lateral wobble.

Not one of the bike shops near me will service it so a replacement is perhaps in order although I am Stateside again soon so could pick up a WI replacement if this is the one to go for.

I have seen this one:

http://eclipsebikes.com/product_info.php?products_id=68

and wonder if others have used it?

The front freewheel is hugely important at these crank speeds so I am happy to not skimp on this part!

Thanks

 

[district9prawn]

Just wondering if anyone made progress with the rather expensive 200A VESC? Looked like a couple people were going to try it?

400 gbp was too much to swallow but luckily the fellow selling them had some blank pcbs left. Parts from mouser cost about 200 usd.

I tested the board on my 3210 bike for about a week before returning to the original 6 fet vesc. It's probably a bit overpowered for the 3220 as well but it should be super reliable at 14s and 200A battery.

Do I understand correctly that these units run in sine wave, so better efficiency, but still sensorless so can suit the astro 3220?

Yes that's right. Sensorless start on trapezoidal commutation should be smoother though, whether on the castle esc's or vesc. Max speed with sine wave is also lower than trap control, but you can more than make up for it with field weakening on foc control

I've also been playing around with a $20 encoder pcb from ebay. Gluing a magnet to the shaft end and mounting the board with the sensor IC a few mm away is quite easy and gives 14 bit resolution position info for smooth startup. On Dave's newer gearboxes with the enclosed motors, perhaps the motor end piece could be extended and the pcb mounted and hidden.

 

[tangentdave]

Ham, pick up a standard Cyclone FW: http://sickbikeparts.com/front-freewheel-cyclone/. Luna also sells an equivalent, there are cheaper versions available from cyclone-tw.com. The $50 cyclone FW is nicer than the $20 but both use two rows of bearings so will freewheel better than the White Ind FW with a bearing on only one side.

I had a VESC6 running with the 2nd gen kit at 14s until tiny puff of smoke from the back of the board, likely a voltage spike. Have a couple VESC6's from Flypsky on the way to try again. I'd really rather not switch to 12s voltage just to use the VESC6, but it is quite nice. Any brave ES'ers been using 14s into the VESC6? Maybe a few more capacitors on the input line?

 

[Ham]

Thanks Dave, I'll see if there are any UK suppliers of them else I'll wait until i land in the USA

 

[E1Allen]

I ordered one of the v1.3 ones. Hopefully I'll see it by the end of September. I like that you can change modes on the fly and run fully charged 14s. Plus they have bt modules so you can use Android/apple watches and monitor data real-time.
I plan to run it in FOC. So quieter plus with the vesc you can manipulate all sorts of options. Throttle curves, motor speed ect.

 

[cr0m08]

Hey Ham I'm still using my 1st gen WI on my 3220 V1.5 kit and its holding up ok as yet. But for my 3210 V1.5 I needed another freewheel so I sourced one from my LBS. And the easy one to get, was the ACS Crossfire flanged freewheel. Its only new (85kms) but the lateral wobble is not too bad, unlike the really cheap version of the cyclone FW I originally got with the 1680W cyclone kit. I'm sure the more expensive cyclone FW is a lot better, but the cheap one is almost unusable for lateral wobble!
Certainly I think in my case, the ACS makes a very good fix given its local easy sourcing, even if its viewed as not a long term replacement, but an easily accessible local replacement. I would have to order, pay considerable freight and wait, in order the get the stronger cyclone replacement. So for now I'll see how the ACS Crossfire goes.
"district9prawn" and "Dave", thanks for the updates on these vesc esc's. I'm not having issues with my Castle HV's, but always got an eye on what is developing. I think Dave's kits are incredible, with the CC HV, but I'm not going to ignore something that could be even better

 

[Ham]

Thanks Cr0m8, that makes me feel better about giving it a go.

I have finally managed to pry part my WI one and the bearing was a little loose and the whole unit was filled with gunk so I will also be grabbing a new bearing for it too. Although cheaper to buy the new ACS than a new bearing which seems nuts!

 

[Ham]

For education sake can someone highlight to me the difference between these bearings, both have the same 6708 2rs code with the only difference I can see is one has 6w on the end of the code

cheap as chips

https://www.123bearing.co.uk/bearing-6708-2RS.php

x4 the price

https://www.bearingstation.co.uk/Products/Bearings/Cycle_Bearings/Enduro_Bicycle_Bearings/6708-2RS-6W-ENDURO

there may well be an important difference but what is it?

 

[knurf]

there may well be an important difference but what is it?

I going to guess that this is due to brand (Enduro) and the ABEC 3 rating of the more expensive one. Some people took the time to measure and check precision of it, etc. and ultimately assign it a rating. But if it's that much better, I don't know.

 

[Ham]

Thanks Knurf,

a bearing shop in France (no clue why the call went there but hey) just explained to me the materials used will be better with the branded enduro but he said you'd be hard pushed to notice a difference except perhaps in longevity.

Edit: just found tech specs of static load ratings: cheap one is 225 kgf and the more pricey one is listed as 1.535 kN (156kgf per Google).

The cheaper seems stronger and cheaper...now colour me confused

From experience in other leisure activities items can be priced waaaay higher if people see a brand name on the EXACT same product used in another industry...for example...a horse lead rope is a disposable cheap item for a few pounds...put a brand name on it and sell it as a dog lead and it is charged at triple for the same thing...wondering if this the same situation with bike bearings?!

Sorry for derailing the thread a little!

 

[knurf]

Try the cheapo ones first. You could get lucky, might not fail any time soon. Or, they'll pop shortly after, in which case you can try another brand.. Quality ones should have better odds of not breaking on the first few days i reckon.

I try to get SKF when available, and I am pleased the Tangent gearbox now uses this brand The Enduro ones seem more optimized for bicycle use (maybe lighter/weaker) and the cheapo ones more general? I actually had Enduro bearings fail on me, but that was when I used them for another application than they (maybe) were intended for (bike).

 

[Ham]

Seems nuts to me the cheaper one is stronger!

 

[tangentdave]

We don't need precision bearings in the freewheel, ABEC1 is plenty good enough. There is a difference in quality between bearings purchased from China (Ebay or alibaba) and brand name like SKF. In general, dont try to save a few bucks with the cheapest bearings available, pay 5 or 10 bucks per bearing from a bearing supply website.

https://www.123bearing.com

 

[tangentdave]

From Russia with love:

View attachment 1

We've got a Hammershmidt to speed up the cranks which run to a dual freewheel on the motor. Tangent drives the rear Shimano Alfine 8spd directly, 13s10p pack of 30q in the frame. Mikhail says he can pedal to 80kph. This arrangement would also be super useful to add a Beam TS torque sensor between cranks and motor FW...if and when we're ever lucky enough for Grin to finish productizing it...

 

[SlowCo]

Wow, very curious to see if the 8 speed Alfine will be "all fine" with the Tangent power through it and survive...
Very nice build though! 8)

 

[Mugenski]

Im also interested to see if it can handle the power. I'd wouldn't mind that hammerschmidt either, pedaling at 80km/h must make you feel like a boss.

Interesting take on the tensioner. My tensioner is solidly mounted and the chain is pushing/pulling on it in such a way to loosen it. Have to keep my allen keys on me on rides (probably a good practice anyways!)

Clean build!

 

[Ham]

Bearing sorted...found a uk supplier of white freewheel and bearings so got an enduro for half the price the others wanted. Replaced but still concerning amounts of lateral play. Meh.

Love that Russian build.

Alfine 8...been running my 3220 through it for over a year and it is holding up just dandy...could probably do with a service soon though.

My 3220 kit is now mounted and running a stealth bomber style frame and happily the esc is now mounted on an alu heat sink inside the frame out of the elements.

Just completed the new rear caliper mount and waiting on a longer brake line so I can mount my hope stoppers at last.



Some old pike 351 160mm travel forks incoming with a hope front hub being slipped in too.

Now to figure out an on off switch for the CA3 so i dont have to keep unplugging batteries...any ideas welcome...

 

[Solaire]

I m considering getting one of these for on/off, as i m doing a lot of short trips a day.

http://www.nexusmodels.co.uk/sps-safety-power-switch-70v-100-200a-battery-esc-isolator-a72011-emcotec-irc.html

http://wiki-en.hacker-motor.com/index.php/SPS_SafetyPowerSwitch

 

[Ham]

I m considering getting one of these for on/off, as i m doing a lot of short trips a day.

http://www.nexusmodels.co.uk/sps-safety-power-switch-70v-100-200a-battery-esc-isolator-a72011-emcotec-irc.html

http://wiki-en.hacker-motor.com/index.php/SPS_SafetyPowerSwitch

That's neat, pricey but neat. I've been thinking about a standard car battery isolation switch. Car cranking amps can be hundreds of amps...

Not being good with electrics i assume the no load amps running through the system are very low so simply switching on and off with one of these switches is safe and so long as they can handle at least 100 amps continuously then i assume they'd be fine to use???

 

[tangentdave]

A mechanical switch will arc, due to the capacitors in the ESC. Solid state switch won't arc. Arcing is bad, degrades contact surfaces. The no load amps is essentially zero but when you try to attach a 50V battery up to some empty capacitors...arcing occurs until the caps reach bus voltage or the metal contactors are in physical contact...

 

[Ham]

Thanks Dave, I need to learn more about this electron malarky!

 

[Ham]

I have been doing some reading...please correct me if i am wrong and about melt my face off:

For a non arcing power switch/breaker it needs to be able to pre charge the esc before the full current be allowed to flow: this happens with the xt90 anti spark connectors through a c5ohm resistor bridging a gap in the terminal within the xt90 block, allowing a small pre charge current to flow milliseconds before the main current flows through the un resisted connector bullet.

Could the same affect be achieved with a car/boat isloator switch wired in the power cable AND a small resistor soldered in between the terminals of said battery isolator...but have that resistor wired in a inline switch (such as a standard keyed ignition switch) so it is only making the resisted connection when the key is turned.

Like a 2 stage ignition system...1) turn key to complete pre charged resisted circuit and then 2)turn the main isolator switch on after. So pre-charge circuit with a key switch and then main circuit with isolator switch...

Makes sense in my head but could be obviously wrong to an electrics minded person....?

 

[E1Allen]

On the 42nd tOoth. Might need a few more links going from 25-42t

 

[Mugenski]

Anyone have trouble separating the gearset of the new gen kit for cleaning and regreasing? I couldn't get it apart, tried gently but she didn't want to come. Cleaned it out and added some new grease. Shes purring as usual. Went for a nice little 2 hour ride with my pedal only buddy. If only he had a motor I really could have ripped it in this cool weather!

Edit: Went for a rip this evening hooligan style to really test the thermals of the new kit (I've been babying it for a nice break-in period). The way I was riding on the gen1 kit would have had me up into 120-150c range with the talon occasionally thermaling out. On the gen1.5 waterjacket setup I peaked 95c (Still running RO water in the jacket). With the heatsink and a fan on the talon I had no thermal issues there either. Fan is probably overkill but I had something compatible laying around and couldn't help myself. I can only imagine people running with bonded stators are going to see even better temps. It's really quite silly to have this much power on a MTB. I found myself laughing rather maniacally on several parts of the ride. Also using a new backpack for the battery that has both chest and waist straps so catching air isn't so sketchy.

Dave the product you have made is overkill. It's stupid. No mountain biker needs this much power, flat land turns into a paradise of small jumps everywhere you look. I love it.

 

[aCeMadMod]

hi from what I know Dave told he now glue the gearset



it would make cents has he dose Not want you to touch it I guess